Dispensers for flexible sheet material in the form of a web, such as paper towel, cloth towel, tissue paper and the like are well known in the art. Certain of these dispensers output sheet material by means of a dispensing mechanism powered by a direct current (DC) motor. A dispense cycle occurs when the motor is activated to power the dispensing mechanism to extend a sheet of material out from the dispenser. A single sheet may then be separated from the web, for example, by automatic cutting, by manual tearing, or by separation of a single sheet along a perforation line between sheets.
The dispensing mechanisms implemented with such sheet material dispensers typically include a “nip” formed by abutment of a drive roller and a tension roller. Motor-powered rotation of the drive roller pulls sheet material from a supply roll, through the nip, and out of the dispenser. The DC motors implemented in such sheet material dispensers typically provide high armature RPM speeds needed to operate the dispensing mechanism to extend a sheet to the user. The motor is typically mounted directly to a sidewall or other dispenser support structure. The sidewall or support structure which supports the motor may be part of a dispenser chassis which supports the drive and tension rollers.
While the aforementioned types of dispensers are quite good, there is opportunity for improvement. For example, the DC motor and any gears internal to the motor and/or gears external to the motor used to power the dispensing mechanism can be noisy and can produce vibration. Noise and vibration produced by operation of these, and other, moving parts can be transferred to the dispenser chassis or other support structure to which the motor and gears are attached. The chassis or other support structure can amplify such noise and vibration because such parts are typically made of lightweight plastic and can vibrate, thereby producing resonant noise. The dispenser housing can also provide a type of chamber which amplifies the noise and vibration. All of this dispenser noise is apparent and distinctly audible to a person using the dispenser. The user may unfairly perceive that the audible noise is an indication that the dispenser is of poor quality and workmanship.
Various attempts have been made to lessen or minimize noise and vibration caused by motors and motor-powered moving parts, but these approaches are not optimally effective for use in automatic sheet material dispensers. For example, U.S. Pat. No. 8,616,489 discloses a paper towel dispenser with a rubber isolator between the motor and chassis. An isolator, however, is an extra part and represents an unnecessary cost item in a dispenser product sold into a fiercely competitive market. Motor mounts such as in U.S. Pat. Nos. 4,452,417 and 5,449,153 represent other attempts to dampen motor noise and vibration but accomplish this by implementing additional mounting parts and components which add cost and complexity.
It would be an advance in the art to provide improved sheet material dispensers for paper towel, tissue paper and other materials which would operate quietly with reduced or essentially user-imperceptible noise from motor operation and motor-powered moving parts, which would provide the manufacturer with the opportunity to both provide for quiet dispenser operation with fewer parts and which would generally have improved performance relative to existing dispensers.